Hi.
After entering failsafe mode and accessing the console via serial port, is it possible to continue to boot without restarting? What's the command to do that?
Is it possible to do a "strace" for the boot process?
Thanks.
If you entered failsafe mode - you have indeed booted the device. Can you clarify your statement regarding 'continue to boot'?
You should be able to press the Enter key to login.
To run a userspace program during boot...from serial?
No. What issue are you attempting to solve?
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Failsafe mode is an interruption of normal boot. It doesn't mount overlay, doesn't apply configuration, doesn't start network, services, etc. Failsafe shows a simple busybox prompt. Enter just shows the prompt again.
I built a custom image. I just added some config files in /etc. Boot process hangs very soon after the failsafe prompt. I can enter failsafe, mount overlay, but that's as far as I can get with failsafe mode. I think it's ubusd that freezes, but I need to investigate why.
The other method would be is to set the kernel bootargs "init=/usr/bin/strace - - -f /sbin/init", but that would output a lot of text from a lot of programs and it will be very difficult to find out which one froze. I was looking for a more simple step-by-step boot process starting from the failsafe prompt so that I could debug each command, one at a time.